[Left ventricular relaxation property evaluated by isovolumic relaxation flow].

The blood flow recorded in the center of the left ventricle (LV) during the isovolumic relaxation period, i.e., isovolumic relaxation flow (IRF), was evaluated by pulsed Doppler echocardiography. The subjects consisted of 17 normal persons, 12 patients with angina pectoris (AP), 63 with old myocardial infarction (OMI), 16 with hypertrophic cardiomyopathy (HCM) and 16 with dilated cardiomyopathy (DCM). In the normal subjects, the IRF showed a laminar flow and it was directed from the center of the LV toward the apex. The maximum velocity of the IRF coincided with the second heart sound. In the patients with heart diseases, the IRF was classified into three patterns. Type A, in which the IRF was directed toward the apex of the LV: This pattern was observed in two different patient groups from the standpoint of LV wall motion and LV ejection fraction (LVEF). One group had either a normal LVEF without wall motion abnormalities or normal LVEF with a small area of abnormal wall motion in the anterior and/or apical portions. The other group had various LVEF with abnormalities of wall motion in the posterior and/or inferior portions. The duration of the IRF in type A was prolonged in AP (142 +/- 35 msec), OMI (152 +/- 14 msec), HCM (166 +/- 33 msec) and DCM (171 msec) when compared with those of the normal subjects (119 +/- 35 msec). The acceleration time (time interval from the beginning of the IRF to the point of the maximum flow velocity) in the normal subjects was 25 +/- 8 msec, but they were prolonged in AP (37 +/- 12 msec), OMI (59 +/- 22 msec), HCM (64 +/- 18 msec) and DCM (58 msec). The acceleration rate (increment of the flow velocities per sec) was significantly decreased in AP (8.9 +/- 3.2 m/sec2), OMI (4.5 +/- 2.7 m/sec2), HCM (4.5 +/- 1.1 m/sec2) and DCM (3.7 m/sec2) when compared with those of the normal subjects (12.6 +/- 4.0 m/sec2). Type B, in which the IRF was directed away from the LV center to the base of the LV: The patients with this type had slightly depressed LVEF with moderately extended abnormalities of wall motion in the anterior and/or apical portions. Type C without discernible IRF: The patients with this type had severely depressed LVEF with generalized abnormalities of wall motion. It was concluded that the patterns of the IRF are affected by regional wall motion and the IRF seems to be caused by LV relaxation.